Fixed. The friction disc is splined to the transmission input shaft; the pedal controls the pressure plate bolted to the engine flywheel.
Originally Posted by SergioK
The clutch pedal and pressure plate are controlled via a hydraulic system. ... The CDV aims to slow down the actual engagement of the clutch if you simply 'pop' your foot off the clutch pedal.
Partially incorrect. The design intent is to protect the driveline from "dumping" or "popping" the clutch as described. However it most certainly does interfere with normal shifting. The restriction is asymmetric--the restriction is greater when engaging than disengaging the clutch--and the orifice in the valve is so small (~10% of the unrestricted cross-sectional area) that the system is not operating in the linear range. That is, the movement rate of the clutch linkage is not in constant proportion to the movement rate of your foot; it varies with the speed of release.
Originally Posted by BmwFlooner
That was my understanding, and that it's something that doesn't interfere with normal shifting.
The net result is that the CDV makes it exceedingly difficult to achieve consistent, smooth clutch engagement, because the precision with which the clutch fork responds to pedal travel is significantly reduced. The non-linearity makes it hard to compensate for the minute added delay because the delay is not constant.
(The above applies to the E9x valving. The F30 is no doubt similar if it has a CDV, or "lock valve" as it is officially called.)
2011 335xi Individual 6MT - Azurite Black Metallic / Oyster & Black / Anthracite Maple + all the good stuff
N47° 35' 30.13" E11° 10' 33.36"
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Last edited by Zeichen311; 04-30-2013 at 12:15 PM.